I just got my car back from some maintenance (oil, breaks...) and took the car for a drive out of town. (94 octane)

I ended up filling with 91 octane about 2 hours into the trip (the station didn't have 94), about 10 minutes after that my engine light came on.

I had the tester in the car and pulled P0011. Arrived at my destination and drove the car for another 2 days around town when all of a sudden (same tank of 91) the light went off. I have since filled the tank with 94 again and the light has yet to return, but I was aiming to get ahead of this should I run into the same situation.

Is it normal for 91 to cause this problem? is there anything preventative I could do?

Thanks,